Starting method for internal combustion engine

Abstract

Starting method for an internal combustion engine at least one cylinder whereof is equipped with a starting valve connected to a source of compressed fluid, said fluid being introduced into the cylinder or cylinders when the pistons are in the combustion phase of the engine cycle, whereby the opening lead of the exhaust valve or valves of each cylinder equipped with a starting valve is temporarily reduced to improve utilization of the energy contained in the starting fluid.

I claim: 
     
       1. A method for starting an internal combustion engine having a crankshaft, at least one working cylinder with a piston connected to the crankshaft for reciprocation between an initial dead center position and a final dead center position in a combustion stroke, the cylinder being equipped with an exhaust valve that opens during normal running of the engine no later than a preselected angle of the crankshaft in advance of the final dead center position of the piston in the combustion stroke and a starting valve connected to a source of compressible starting fluid under pressure, the method comprising: opening the starting valve to introduce pressurized starting fluid into the cylinder during the combustion stroke in a starting sequence of the engine and temporarily retarding the opening of the exhaust valve beyond said preselected angle of the crankshaft during the starting sequence to improve utilization of the potential energy contained in the pressurized starting fluid.   
     
     
       2. The method of claim 1 wherein the step of temporarily retarding the opening of the exhaust valve comprises servoing the retardation of the exhaust valve opening to the duration of the starting sequence. 
     
     
       3. The method of claim 1 or 2 wherein the step of temporarily retarding the opening of the exhaust valve comprises retarding the exhaust valve opening by an angular amount equal to at least one-third of said preselected advance angle.